Notes on Staphylococus
Rahul's Noteblog
Notes on Bacteriology
Notes on Staphylococus
General Staphylococus notes:
• Gram positive cocci.
• They have little virulence, but can sometime cause serious infections.
• S. epidermidis reside in the skin under dry and salty conditions.
• Catalase positive.
• Also present in nostrils.
• S. aureus causes skin and wound infections, and food poisoning.
• S. saprophyticus causes urinary tract infections.
• Are part of the normal flora, but can cause infections in immunosuppressant individuals.
• S. aureus also causes nosocomial pneumonia and surgical site infections.
• Hospital strains are often resistant to a variety of antibiotics.
• They compete for nutrients with other skin colonizers, and produce antimicrobial substances against P. acnes.
• Are pyogenic, meaning, can produce pus. Infection accompanied by inflammation, swelling, redness, pain and even fever.
• They grow aerobically or anaerobically, and are salt tolerant.
Genus: Staphylococcus.
• Gram +; cocci; catalase +.
S. epidermidis: skin.
• Thrive on human skin.
• Causes infection in stitches after surgery.
• Infection can be lead to the heart, leading to subacute bacterial endocarditis.
• Coagulase -.
S. saprophyticus: UTIs.
• Coagulase -.
S. aureus:
• It produces coagulase, which leads to the production of blood clotting staphylothrombin.
• Causes blood to clump.
• Protein A of staphylococcus is a virulence factor, leading to inactive IgG.
• Alpha-toxin is also produced by staphylococcus, leading to cell-death.
• Other virulence factors: fibronectin-binding protein, leukocidin, enterotoxins and toxic shock syndrome toxin-1.
• They are coated with proteins so that the body’s immune defense sees them as a local.
• Beta-hemolytic; yellow on blood agar; catalase +; coagulase +.
• Ferments mannitol.
• Nose and skin.
• Food, hands, sneezing, surgery, lungs of cystic fibrosis patients, CGD, IV drug abuse, neutropenia, food poisoning.
Pathogenesis:
• Protein A inhibits pathogenesis.
• Entertoxins A-E.
• TSST-1.
• Coagulases produce fibrin clot.
• Cytolytic toxins form pores.
• Exfoliatins cause SSS.
Diseases: gastroenteritis, infective endocarditis, TSS, impetigo, pneumonia, surgical infections, and osteomyelitis.
Treatment: methicillin and nafcillin.
MRSA: vancomycin and fusidic acid.
Additional Readings:
Basic Bacteriology
1. General Microbiology
2. Growth Medias and Oxygen Requirements
3. Staphylococus
4. Streptococcus
5. Enterococcus
6. Bacillus
7. Listeria
8. Corynebacterium
9. Actinomyces
10. Nocadria
11. Mycobacterium
12. Clostridium
13. Neisseria
14. Pseudomonas
15. Legionella
16. Bordetella
17. Francisella
18. Brucella
19. Campylobacter
20. Escherichia
21. Shigella
22. Klebsiella
23. Salmonella
24. Yersinia
25. Proteus
26. Vibrio
27. Pasteurella
28. Haemophilus
29. Bacteriodes and Prevotella
30. Treponema
31. Borrelia
32. Rickettsia
33. Coxiella
34. Ehrlichia
35. Chlamydia
36. Mycoplasma
37. What is an ELEK's Test?
38. Causes of Orchitis
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Page accessed on: July 29, 2010, 11:57 am.